Origin
Once she finds out Cain murdered her sister, she wants revenge and so she hunts him down. She is confronted by the League of Assasins, Bronze Tiger included, and she fights them all. Remember this is practically before she even started her 'career'.
Just so we get it straight, here is what Bronze Tiger thinks of Shiva:
"When you beat Shiva, it was obvious to any of us who'd been in on it [...] Only the entire league could've taken down Shiva [...] This was a long time ago, she wasn't much older than you are now. She wasn't unbeatable yet".
And in case people need refreshing on who Bronze Tiger is:
Here he one-shots Batman:
When they later meet, and Batman has prepared to fight him one on one, Batman remarks on how Bronze Tiger still nearly had him, and only manages to slow him down, until the fight is interrupted:
Fights Batman. She hits him so fast, he doesn't even see the kick coming. He says she easily has the hitting power or Ra's al Ghul and the speed and agility of Sensei. Says his only hope of winning is coming close and see if he can out-muscle her. Jason comes to Batman's aid, sucker-punches her, with Batman taking advantage of this and hitting her with everything he's got, but he's amazed she can take all that and not go down.
Trains Robin. He says she is faster than anyone he's ever seen, maybe even faster than Batman:
Just by looking, she is able to tell the tehniques that were used in order to kill people:
"You're something else entirely. A dark myth. You're what even the most cold-blooded among us fear. If I die at your hands, I become part of the myth". Dodges bullets and easily kills the assasin.
A little info on Shadowdraon, a martial artist wearing a technological armour enhacing his every physicall atribute. Confronts Superman. Notice how besides the heartbeat, he is invisible to Superman's senses, and uses a thunderclap to find him. And most of all, notice the insane speed he has, making Superman even say that he is not used fighting somebody faster than he is: